Has Calvin Klein, 67, split from his 21-year-old model boyfriend?

The 67-year-old fashion designer made an appearance at the Dream Downtown hotel's Ph-D nightclub in New York on Sunday without 21-year-old model Nick Gruber and now insiders claim the couple – who began dating almost two years ago – are no longer together.

A source told the New York Daily News newspaper: 'They're on a break. They could get back together, but who knows'

Back then: The couple, pictured in December, are said to be 'on a break,' but have reportedly had an on-and-off relationship since getting together two years ago

Friends of the pair describe their relationship as 'on-and-off' but nightclub promoter Daniel Nardicio insists Nick wants to spend the 'rest of his life' with Calvin.

Mr Nardicio – who says he is currently working with Nick – told the Village Voice newspaper: 'He's been very open with me about how he and Calvin met and how he really loves Calvin and wants to spend the rest of his life with him.

'He was pretty open about his sexual past, and is thinking of becoming a trainer/nutritionist.'

Last year, Calvin threw a huge party to celebrate Nick turning 21.

A leaked copy of the invitation revealed it read: 'In the spirit of the New Year and in celebration of Nick Gruber's birthday, please join Calvin Klein for dinner and drinks at Indochine Jan 21 at 9pm. It will be the hottest ticket for New York's gay and fashion elite.'

Pretty pair: Looking good together despite the 46-year age gap, the couple often matched outfits at A-list events

Despite the 46-year age difference between the two, commentators, including Huffington Post, said the couple seemed to make each other very happy.

They have graced the guest lists at many a VIP bash in recent months, including a costumed Halloween party and at the Young Adult premiere in December.

The stylish duo were often seen in matching outfits – be they all white, all black or leather-jacketed.